1. Field of the Invention
The present invention relates to a packing used for joining end portions of electrical wire tubes with each other, which protect electric wires and so on, and to a coupling using the packing.
2. Description of the Related Art
A “screwless coupling”, which has been disclosed in Japanese Utility Model Application Laid-open No. Hei 06-6260, refers to a water-proof type coupling used for coupling electrical wire tubes with each other, which is used as a power distribution installation in nuclear power facilities and the like.
Such “screwless coupling” includes a metal body and a grip case, which is engaged with a grip portion of the body. A water-proof packing is arranged within the body.
The water-proof packing is engaged with a center stopper protruding from an inner peripheral surface of the body, and an outer peripheral surface of the water-proof packing is adhesively fixed to the inner peripheral surface of the body with a water-resistant adhesive. Further, in the “screwless coupling”, an arc-like closing plate is needed to close an opening of the body.
However, in such screwless coupling, there is a problem in that it is troublesome to adhesively fix the water-proof packing to the inner peripheral surface of the body.
Further, a high degree of skill is required to adhesively fix the water-proof packing to an accurate position of the inner peripheral surface of the body.
In addition, the arc-like closing plate is needed, and hence a procedure for the screwless coupling becomes more troublesome.